Metal-oxide-semiconductor (MOS) technologies have many advantages and such technologies are widely used in the silicon semiconductor industry. The requirements for gate quality oxide-semiconductor structures are manifold: (i) low interface state density D.sub.it &lt;10.sup.11 cm.sup.-2 eV.sup.-1, (ii) low trap density N.sub.t .ltoreq.low 10.sup.11 cm.sup.-2 in the oxide film, (iii) thermodynamic interface and oxide stability, and (iv) interface and oxide reliability in particular related to oxide damage caused by injection of (hot) carriers.
For compound semiconductors, prior art, for instance M. Passlack et al., Appl. Phys. Lett., vol. 68, 1099 (1996), Appl. Phys. Lett., vol. 68, 3605 (1996), and Appl. Phys. Lett., vol. 69, 302 (1996) reported the fabrication of oxide-III-V compound semiconductor structures using in situ deposition of gallium oxide molecules on GaAs based epitaxial layers while maintaining an ultra-high vacuum (UHV). The thus fabricated Ga.sub.2 O.sub.3 -GaAs interfaces have an interface state density D.sub.it of 2.5.times.10.sup.10 cm.sup.-2 eV.sup.-1 and the GaAs band gap is fully accessible. However, the properties of oxides fabricated in prior art are inadequate for applications mainly because of the presence of defects related to oxygen vacancies; the breakdown field E.sub.BD and the specific resistivity .rho. are typically less than 3 MV/cm and lower than 10.sup.13 .OMEGA.cm, respectively, and trap densities as high as 2.times.10.sup.12 cm.sup.-2 have been found. This gives rise to stability and reliability problems including charge trapping, carrier injection, long term drift of device parameters in accumulation and inversion, and eventually, oxide degradation and breakdown. Consequently, the performance of unipolar and bipolar devices is affected and the fabrication of stable and reliable metal-oxide-semiconductor field effect transistors (MOSFET) based on compound semiconductors has been impossible.
Accordingly, it would be highly desirable to provide new methods of manufacturing which overcome these problems. Thus what is needed is a new and improved method of manufacturing a gate quality oxide-compound semiconductor structure. What is also needed is a new and improved method of manufacturing a gate quality Ga.sub.2 O.sub.3 -compound semiconductor structure. What is also needed is a new and improved method of manufacturing a gate quality Ga.sub.2 O.sub.3 -compound semiconductor structure wherein the density of defects related to oxygen vacancies is adequate for MOSFET applications. What is also needed is a new and improved method of manufacturing a gate quality Ga.sub.2 O.sub.3 -compound semiconductor structure wherein the oxide specific resistivity is adequate for MOSFET applications.
What is also needed is a new and improved method of manufacturing a gate quality Ga.sub.2 O.sub.3 -compound semiconductor structure wherein the oxide breakdown field is adequate for MOSFET applications. What is also needed is a new and improved method of manufacturing a gate quality Ga.sub.2 O.sub.3 -compound semiconductor structure with oxide trap density.ltoreq.10.sup.11 cm.sup.-2. What is also needed is a new and improved method of manufacturing a gate quality Ga.sub.2 O.sub.3 -compound semiconductor structure with oxide trap density.ltoreq.10.sup.11 cm.sup.-2 and interface state density.ltoreq.10.sup.11 eV.sup.-1 cm.sup.-2. What is also needed is a new and improved method of manufacturing a gate quality oxide-compound semiconductor structure with improved stability and reliability. What is also needed is a new and improved method of manufacturing a gate quality oxide-compound semiconductor structure which allows the implementation of stable, reliable, and manufacturable accumulation and/or inversion mode devices using compound semiconductors. What is also needed is a new and improved method of manufacturing a gate quality Ga.sub.2 O.sub.3 -compound semiconductor structure which is relatively easy to fabricate and use.